With increasing public concern over the quality of the environment, a significant need has arisen for equipment which is capable of accurately and economically testing various environmental conditions. The present invention, while suitable for employment in any system performing automated chemical analysis, is particularly useful for continuously and automatically obtaining a relatively particle-free sample of liquid from a body of water, such as a lake, stream or municipal water supply.
Conventionally, it one wishes to measure the level of pollutant, the biological oxygen demand or some other parameter of a body of water, one would take a sample of the water and submit it to an appropriate quantitative chameical analysis. These chemical tests generally comprise a number of steps involving the mixing and reacting of a predetermined amount of the sample or reacted sample with specific quantities of various chemical reagents.
These tests are best carried out individually by relatively highly skilled personnel. Naturally, if one wishes to use a test to obtain data continuously or at frequent intervals and thus construct an accurate and complete picture of the state of water quality over a period of time, conventional manual testing is quite expensive. Moreover, if one desires to perform a continuous analysis with automated equipment, it is necessary to have a technique for taking a continuous sample. Simply diverting a portion of a liquid from the body will not provide acceptable results because the thus obtained sample tends to include solid particles which interfere with the proper operation of automatic analysis equipment.